In the prior art, it is common practice to provide solenoid electromagnetic braking devices for motor shafts. Such electromagnetic brake members have the characteristic of operating instantaneously which puts undue stress on the motor.
The device of the present invention employs a solenoid operated valve which meters compressed air or a fluid flow to a diaphragm housing. The solenoid is provided with an adjustable metering valve, is connected in parallel with the electric motor and is of the normally closed type. Thus, when the energy to the motor is shut off, the energy to the solenoid is automatically shut off interrupting the flow of compressed air to the diaphragm housing. A plunger, operable by the diaphragm, is retracted permitting compression spring means associated with a pressure applying means to actuate the brake means. When the motor is energized, the solenoid is activated to direct the compressed air to the diaphragm housing, actuating the plunger to disengage the brake means.